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Mid-Compact Rising (on the FC-9000)

Six or seven years back, the upstart, hotshot crankset was the Compact. Offering a light 50T/34T gearing, it gave so equipped cyclists the ability to climb up hills at a higher, more comfortable cadence. This relaxed climbing pace, to a certain extent, came at the expense of speed. Riders powerful enough to max out the 50T chainring are left wanting in terms of top end pace.

On the other side of the coin are the Standard chainrings. These commonly have 53 or 52-tooth large rings and 39-tooth inner rings. These have been de facto for so long that the setup earned Standard moniker. And we're talking about the modern Standard here. Older Standard cranks even came in at up to a whopping 54T/44T! Although these ring combinations are still around, they're now almost exclusively for time-trial use.

All things equal, Compact will be outpaced by Standard in the top end of the speed spectrum as Compact users will eventually run out of cogs or spin their lungs out trying to keep up with Standard riders on long flats. Conversely, Standard crank users will be finding themselves grinding (and possibly cramping) their way up mountains while Compact-equipped Cyclists pass them by, spinning merrily ahead. While this may not be a big issue in shorter climbs, this would definitely manifest itself in longer, sustained climbs.

Any self respecting Cyclist must, of course, select which chainring combination is best for his particular type of riding or terrain...which works out around 90% of the time. However, the 10% needs to be addressed every now and then. It can't be avoided that that one needs to ride outside of his usual comfort zone.

For lack of a better term, an inappropriate crank is less of an issue for the guy with Compacts on the flats. However, it may certainly break the guy on Standards going up a steep mountain...... which is perhaps the reason why most roadie built-bike offerings these days often come with Compact gearing as standard.... as opposed to 'Standard' gearing.

Yes, Triple Cranks do exist in the road cycling universe. However the added weight, cost and complexity of these systems coupled with limited availability makes this an option only for people who really really need it badly enough.

Enter: The Mid-Compact

Rapidly gaining popularity is a new crank setup: The Mid-Compact. Some call it the semi-compact and some even choose to ignore it altogether and dump it into the compact category. For us, however, this new in-between gearing definitely deserves to be in its own class.

The Mid-Compact crankset first popped up in our radar in 2010. This was when SRAM introduced it as part of their Red lineup. Campagnolo and just recently, Shimano joined the bandwagon and introduced their own Mid-Compact cranks in their top tier Groups. Back when the Mid-Compact initially appeared, some people scoffed at the configuration as 'confused' and 'undecided'. However, this in-between range is what makes this configuration special.

With its 52T/36T tooth count, the Mid-Compact loses very little in terms of top speed, only giving up a tooth compared to a Standard crank's 53T large ring. Little is sacrificed on climbs as well. The Mid-Compact's 36T small ring can keep up with the 34T compact crank, only giving up 2 teeth to the full pledged climbing ring.

Spot the Diff: Mid-Compact (L) vs. Compact (Installed)

The Numbers

To give us a better idea on where the Mid-Compact sits in the gearing hierarchy, we made this simple gear ratio chart. This chart focuses specifically on Chainring-Cog ratios which are computed as Chainring ÷ Cog. Layman's terms: one revolution of your selected Chainring (Vertical) will spin the selected Cog (Horizontal) exactly that number of times.

e.g. A 53T crank will spin a 28T cog 1.893 times per complete revolution.

Depicted in the Cogs column is the Shimano CS-9000 11-Speed 12-25 cassette. The 28T and 11T cogs (in parenthesis) are included in the chart to further illustrate how they play with Standard, Mid and Compact Cranksets. With the way equipment development is progressing, we wouldn't be surprised to see all of these thirteen cogs in a production cassette in the not too distant future.

To focus purely on the merits of the crank gearing, we shall leave discussions on cassette selection, crank length, tire thickness, inflation pressure, cadence, leg strength and what have you off the table.

Everything absolutely equal, the Mid-Compact effectively bridges Standard and Compact. The Mid's large chainring performs close to the Standard's large ring while its small chainring performs closer to the Compact's small ring.

In other words:

The Mid-Compact is like a Standard on the large rings and like a Compact on the small rings.

To further illustrate, we took the average gear ratios of three Cranksets and the 12-25 cassette and compared them to each other.

On the Large rings (top speed scenario) where Standard is preferred, the Mid-Compact is only 1.89% slower vs. Standard. The Compact is 5.67% slower.

On the Small rings (climbing scenario) where the Compact is preferred, we find that the Mid-Compact is 5.56% harder to crank than the Compact. Compare that to the Standard's Small ring, which is a whopping 12.79% harder crank across the cassette range!

This jack-of-all-trades approach may very well make the Mid-Compact the new Standard. We're already seeing a lot of the word Mid-Compact here.

Shimano FC-9000 52/36Our Mid-Compact crankset came in the form of Shimano's radical FC-9000. With four asymmetrically placed spider arms, this new design shaves quite a few grams off of a comparable five armed spider. The design also offers a great long-term advantage... all chainring sizes use one, for lack of a better term, bolt circle diameter (BCD). A minor miracle of sorts, this means that all chainrings are interchangeable! Switching from Compact to Mid to Standard only requires chainrings as the crankarms and spiders are standard.

At a manufacturer claimed weight of ~600g, the four-armed design and improved hollow rings/cranks managed to shave off 60 or so grams off the 7900 version. The four arms are positioned in areas where strength is most needed during the crank cycle, which rather makes sense. The new aesthetic, however, is polarizing. In fact, a lot of people hate the design outright. However, it's function over form and for more than a few, it's a real looker in itself. The workmanship and quality of materials on the crank, as well as for all the 9000 series components, is top notch.

On The RoadImmediately noticeable is the Mid-Compact's large chainring performance on the flats. Off the bat, we observed our cadence drop compared to our previously installed Compact crank while maintaining the same pace. Upping the ante to our normal riding cadence brought about even more speed! It's been a while since we rode Standards. And while we technically still aren't on Standards, the Mid-Compact's large ring pulls off a very good impersonation.

The same can be said about the 36T small ring. On rolling hills, this can definitely hold its own against the Compact's 34T and in this scenario, may actually be better as there is less need to shift the RD while transitioning from uphill to downhill to uphill.

On long climbs, we did not observe any major difference between the Mid-Compact's 36T small ring and the 34T ring our our compact. In fact, the 36T ring made us climb a bit faster than our previous record using the 34T. This may be due to many different factors but at the very least, we can comfortably say that the 36T is adequate for all but the most thigh busting of ascents.

In terms of technical functionality, we can't see any fault with the FC-9000. Adequately stiff, it simply does it's job well.

Convert to a Mid-Compact and pair it with an 11-28 and you can go virtually anywhere. We may have well found the holy grail of chainrings.

Verdict

The do-all Mid-Compact just makes sense as Cyclists no longer need to choose between Standard and Compact. Everyone can just get a Mid-Compact and do tailor fitting on the cassette end. This will be the new 'Standard' in a few short years.

Great article...i used to have a compact on my first road bike and had to ask a lot of people what's the difference between compacts and standards...i never really got such a clear answer as you laid out in this article, just some "oh it's almost the same..." answer. thanks! and then i got one with a standard, which i felt was totally different and really bumped my speed up the flats. dont have the mid-compacts yet, but now i know the differences.

11-28 on mid-compacts is the perfect go-anywhere combination. You have both top and bottom ends of the speed spectrum covered.

Personally I prefer corncob gearing (1 tooth difference between cogs) and since I really don't do hardcore climbs, I'd sacrifice the 28T and just top off at 25T. I also gave up the 11T top gear in favor of the 12T again for the sake of corncob gearing. This gives us a 12-25.

Gearing is highly subjective and what i reco is see how your legs react to your current gearing and adjust from there.

Wow that was a really useful article! The absolute best I've found so far about this new trend of "Mid-Compact" gearing. At first it may seem like losig only 1 tooth on the large crank and just 3 on the small won't make a difference but according to your numbers, it actualy makes sense! I really see no more reason to use a 53/39T.

I tryed for the very first time a compact 50/34T on Sram Rival for my previous bike until I get an accident, I loved it sooo much more as now I may have found a killer deal for my new "used" bike all on Red but it came with 53/39T and I struggle sooo much in uphills!

What I wonder is if I have a 12-26 cassette, would I be better with a 50/34T ratio than 52/36T since I don't have that nice 28's climbing gear? :/ It would cost me just too much to change the whole cassette too just for an extra step but then I tell me that 50/34T might be too "weak" if my max gear behin is 12 rather than 11? What would be your recommandation sir?